棒材纵向磁通感应加热数值模拟研究

Numerical simulation of longitudinal flux induction heating of bars

利用ANSYS有限元软件中的电磁-热耦合技术,通过建立有限元模型,分别采用单项方波电流与正弦波电流对棒材感应加热,分析了在加热过程中,不同电流频率、电流密度、占空比的方波电流和正弦波电流对工件的加热效果及影响规律.结果表明:增大方波电流与正弦波的电流强度和频率都会提高工件在相同加热时间所达到的温度.相比正弦波电流,占空比20%方波电流在相同时间内对工件的加热速率更快,但由于集肤效应,使工件径向温度差相对较大.且在电流有效值固定情况下,减少占空比可以增加对工件加热速率,增加电流的有效利用率.同时,模拟计算值与实验值进行了比较,结果基本吻合.因而证明采用方波电流感应加热对加热速率以及实际工艺有更好的效果.

The electromagnetic and thermal coupling technology in ANSYS finite element software was used to establish the finite element model. The single square wave current and sine wave current were used to induce the heating of the bars. The different current frequencies and current density were analyzed in the process of heating. The effect of square wave current and sine wave current of duty cycle on the heating effect of workpiece was discussed. The results show that increasing the current intensity and frequency of the square wave current and sinusoidal wave can increase the temperature of the workpiece at the same heating time. Compared with sinusoidal current,the duty cycle of 20% square wave current can heat the workpiece faster in the same time,but the radial temperature of the workpiece will be increased because of the skin effect. The difference is relatively large. Under the condition of fixed current effective value,reducing the duty cycle can increase the heating rate of the workpiece and increase the effective utilization rate of the current. At the same time,the simulated values were compared with the experimental values,and the results were in good agreement.Therefore,it is proved that square wave current induction heating has better effect on heating rate and actual process.